JP2013154282A - Photocatalyst and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a photocatalyst in which air cleaning by visible light irradiation or the photocatalytic activity such as anti-bacterium and anti-virus are excellently exhibited, and the decreasing of a film physical property after long-term use is not hardly caused; and a method for manufacturing the same.SOLUTION: A photocatalyst includes a photocatalyst layer that contains a photocatalyst particle in which a metal compound is supported in a photocatalytic substance on a resin base material, wherein the content for each unit volume of the photocatalyst particle increases from the resin base material side of the photocatalyst layer continuously or stepwisely toward the surface side of the photocatalyst layer. A method for manufacturing the same is disclosed.

Description

  The present invention relates to a photocatalyst and a method for producing the same, and in particular, photocatalytic activities such as air purification, antibacterial and antiviral are expressed well by irradiation with visible light, and the physical properties of the photocatalyst layer are hardly deteriorated even after long-term use. The present invention relates to a photocatalyst and a method for producing the same.

  As a photocatalyst, titanium oxide that exhibits activity under ultraviolet irradiation is widely known, but in recent years, it exhibits activity under visible light irradiation for the purpose of use in an environment where the amount of ultraviolet irradiation is small such as inside a house. Nitrogen-doped titanium oxide, sulfur-doped titanium oxide, tungsten oxide, and the like have been found as visible light responsive photocatalytic materials. However, these visible light responsive photocatalysts have visible light activity, but have not yet obtained sufficient photocatalytic activity. In order to solve this problem, a photocatalyst in which a copper divalent salt or an iron trivalent salt is supported on a titanium oxide surface doped with metal ions is disclosed (for example, see Patent Document 1). However, in order to obtain such a photocatalyst, heating and baking at a high temperature is necessary, and it is difficult to form a photocatalyst film directly on a resin substrate.

  On the other hand, a method of forming a metal oxide thin film without applying heat and baking at a high temperature by irradiating a laser beam having a wavelength of 400 nm or less after applying a metal organic compound on a substrate is disclosed (for example, , See Patent Document 2).

JP 2010-104913 A JP 2001-31417 A

  Although the photocatalyst of Patent Document 1 has high visible light activity, in order to form a photocatalyst layer on a resin substrate, it is necessary to apply and dry a liquid mixture of photocatalyst particles once formed and a binder. In this method, not only the productivity is lowered, but also the photocatalyst particles buried in the binder do not work effectively, and on the contrary, the photocatalyst layer is deteriorated by long-time light irradiation, and the film is likely to peel off from the substrate. It was.

  In the method of Patent Document 2, a plurality of organometallic compounds are mixed and applied to form a photocatalyst layer including a photocatalyst carrying a metal compound as a photocatalyst having high photocatalytic activity, and then a laser having a wavelength of 400 nm or less. Irradiating light. However, with this method, there is a problem that a photocatalyst layer containing a photocatalyst carrying a desired metal oxide cannot be formed only by producing mixed oxide particles of a plurality of metals, and sufficient photocatalytic activity cannot be obtained. was there.

  The present invention has been made in view of the above-mentioned problems, and exhibits good photocatalytic activities such as air purification by irradiation with visible light, antibacterial and antiviral properties, and film properties are hardly deteriorated even after long-term use. An object is to provide a photocatalyst and a method for producing the same.

  The present inventor has accumulated extensive research. As a result, surprisingly, it has a photocatalyst layer containing photocatalyst particles in which a metal compound is supported on a photocatalyst material on a resin substrate, and the surface of the photocatalyst layer from the resin substrate side of the photocatalyst layer The present inventors have found that the above problem can be solved by a photocatalyst that increases the content per unit volume of the photocatalyst particles continuously or stepwise toward the side, and has completed the present invention.

  That is, the above object of the present invention is achieved by the following configuration.

  1. A photocatalyst layer containing photocatalyst particles in which a metal compound is supported on a photocatalyst substance is provided on a resin substrate, and continuously or from the resin substrate side of the photocatalyst layer toward the surface side of the photocatalyst layer. The photocatalyst body in which the content per unit volume of the photocatalyst particles increases stepwise.

  2. The increase in the content per unit volume of the photocatalyst particles is continuous. A photocatalyst described in 1.

  3. 1. The photocatalyst layer includes at least one binder selected from the group consisting of a fluoropolymer and a silicon compound. Or 2. A photocatalyst described in 1.

  4). A method for producing a photocatalyst having a photocatalyst layer on a resin substrate, comprising: mixing a metal oxide and an organometallic compound to prepare a mixed solution; and applying and drying the mixed solution on the resin substrate. A process for obtaining a coating film, and a process for irradiating the coating film with vacuum ultraviolet light having a wavelength of 200 nm or less.

  5. 3. The liquid mixture described above, comprising at least one binder selected from the group consisting of a fluoropolymer and a silicon compound. The manufacturing method as described in.

  6). 3. The metal oxide is a photocatalytic substance, and the organometallic compound is a precursor of a metal compound supported on the photocatalytic substance. Or 5. The manufacturing method as described in.

  7). Above 1. ~ 3. Or the photocatalyst described in any one of 4 above, or 4. ~ 6. An electronic device provided with a photocatalyst obtained by the production method according to any one of the above.

  According to the present invention, there are provided a photocatalyst that exhibits good photocatalytic activity such as air purification by visible light irradiation, antibacterial, antiviral and the like, and hardly deteriorates film properties even after long-term use, and a method for producing the same. sell.

It is a graph which shows the result of having measured content of the iron oxide in the photocatalyst layer of the photocatalyst body 2 obtained in Example 2 by XPS method.

  The present invention has a photocatalyst layer containing a photocatalyst particle in which a metal compound is supported on a photocatalyst material on a resin substrate, from the resin substrate side of the photocatalyst layer toward the surface side of the photocatalyst layer. , A photocatalyst body in which the content per unit volume of the photocatalyst particles increases continuously or stepwise.

  By having the photocatalyst layer as described above, a photocatalyst body in which improvement in photocatalytic activity and suppression of deterioration in physical properties after long-term use are compatible is obtained.

  Furthermore, the method for producing the photocatalyst of the present invention comprising a step of irradiating vacuum ultraviolet light having a wavelength of 200 nm or less after applying and drying a mixed liquid containing a metal oxide and an organometallic compound on a resin substrate is very It is possible to produce a photocatalyst that has high productivity, is suitable for continuous production, exhibits good photocatalytic activity by visible light irradiation, and hardly deteriorates film properties even after long-term use.

  Hereinafter, the configuration of the photocatalyst of the present invention will be described in detail.

<Photocatalyst layer>
The photocatalyst layer according to the present invention includes photocatalyst particles that absorb and activate light energy to exhibit super hydrophilicity and redox reaction.

  The photocatalyst particles of the present invention have a structure in which a metal compound is supported on a photocatalytic substance having a photocatalytic function. Here, that the metal compound is supported includes a state in which the metal compound is taken into the photocatalytic material at an atomic level and a state in which fine particles of the metal compound adhere to the surface of the photocatalytic material. Such a state where the metal compound is supported on the photocatalytic substance can be observed with a scanning electron microscope or the like. The metal compound has a function as a promoter for the photocatalytic substance.

Specific examples of the photocatalytic substance used in the present invention include, for example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), and the like. Among these, titanium oxide is known to have three types of crystal structures of rutile type, anatase type, and brookite type, and the anatase type is suitable as a photocatalytic substance. The crystal structure of titanium oxide can be identified based on the peak position of the X-ray diffraction spectrum, for example. These photocatalytic substances can be used alone or in combination of two or more.

  A commercial product may be used as the photocatalytic substance, or a synthetic product may be used. As a synthesis method, it can be produced by a known method such as a method of hydrolyzing titanium sulfate or the like or a sol-gel method of hydrolyzing titanium alkoxide. In addition, as in the method for producing a photocatalyst of the present invention described later, a photocatalytic substance can also be obtained by irradiating a vacuum ultraviolet light having a wavelength of 200 nm or less to an organometallic compound that is a precursor of a photocatalytic substance. it can.

The photocatalyst particles according to the present invention are preferably visible light responsive photocatalysts. Examples of the visible light responsive photocatalyst include platinum oxide (PtO ₂ ), oxidation on the surface of a photocatalytic substance such as tungsten oxide (WO ₃ ) or titanium oxide (TiO ₂ ) doped with nitrogen, sulfur or the like as necessary. Examples thereof include photocatalyst particles supporting at least one metal compound selected from the group consisting of gold (Au ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), and copper oxide (CuO).

  Examples of a method for doping nitrogen oxide particles with titanium oxide particles include, for example, titanium oxide particles from urea, amino acids, ammonia, sulfur carriers, thioureas, mercaptans, decanethiols, and thioacetamide at a temperature of 200 to 700 ° C. The method of making it contact with the at least 1 sort (s) of nitrogen compound or sulfur compound selected from the group which is mentioned, the method of mixing the said nitrogen compound and / or sulfur compound in the manufacturing process of a titanium oxide particle, etc. are mentioned.

  Here, “dope” refers to a state in which a doped material is taken into an oxide crystal at an atomic level, and can be confirmed by, for example, a peak shift in an XPS method (X-ray photoelectron spectroscopy).

  The content of the metal compound in the photocatalyst particles is preferably an amount such that the metal atom in the metal compound is 0.01 to 10% by mass with respect to the photocatalytic substance, and is 0.05 to 1.0% by mass. More preferably, it is an amount.

  In the photocatalyst layer of the present invention, the content per unit volume of the photocatalyst particles increases continuously or stepwise from the resin substrate side of the photocatalyst layer to the surface side of the photocatalyst layer. Here, the content per unit volume of the photocatalyst particles is increased not only when the content of the photocatalyst particles themselves is increased, but also with respect to the photocatalytic substance of the supported metal compound, although the content of the photocatalyst particles themselves is not changed. This includes cases where the amount increases. However, it is preferable that the content of the photocatalyst particles themselves is increased from the viewpoint of enhancing the photocatalytic function and suppressing deterioration of film properties after long-term use. The content per unit volume of the photocatalyst particles can be measured by X-ray photoelectron spectroscopy (XPS or ESCA). Further, from the viewpoint of obtaining the effect of the present invention more efficiently, the increase in the content per unit volume of the photocatalyst particles is preferably continuous.

  The photocatalyst layer according to the present invention preferably contains a binder in order to maintain the adhesion of the film. As the binder used in the present invention, a binder having a very slow decomposition rate due to the photocatalytic function of the photocatalyst particles is preferable. Specific examples of binders include, for example, fluoropolymers such as vinyl ether-fluoroolefin copolymer, vinyl ester-fluoroolefin copolymer, tetrafluoroethylene-perfluorofluorosulfonylethoxypropyl vinyl ether copolymer; polyorganosiloxane, sodium silicate, Preferable examples include silicon compounds such as colloidal silica and polysilazane, and vinyl acetate-acrylic copolymers. These binders can be used alone or in combination of two or more. Among these, at least one selected from the group consisting of a fluoropolymer and a silicon compound is preferable. Furthermore, polyorganosiloxane is more preferable because, when forming the photocatalyst layer, crystallization is promoted simultaneously with irradiation of vacuum ultraviolet light having a wavelength of 200 nm or less, and the adhesiveness of the photocatalyst layer is improved.

  The binder content in the photocatalyst layer is preferably 0.02 to 1.5 mass%, more preferably 0.05 to 0.5 mass%, based on the photocatalytic substance.

  The photocatalyst layer may contain other additives as necessary. Examples of the additive include a curing agent that improves coating film adhesion such as an isocyanate curing agent and a melamine curing agent, and an aggregation inhibitor for photocatalyst particles such as a titanium coupling agent.

  The film thickness of the photocatalyst layer is preferably 50 nm to 5 μm, more preferably 100 nm to 1 μm. If it is the range of such a film thickness, it is excellent in photocatalytic activity, and is excellent in transparency and film | membrane physical property.

<Resin substrate>
The resin base material used in the present invention is not particularly limited as long as it has high light transmittance, and the material, shape, structure, thickness and the like can be appropriately selected from known materials. Specific examples of the resin substrate include, for example, biaxially stretched polyester films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, and polystyrene resin. Film, polyolefin resin film such as cyclic olefin resin, vinyl resin film such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) ) Resin film, polycarbonate (PC) resin film, polyamide (PA) resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, etc. Rukoto is possible, as long as it is a resin substrate transmittance of 80% or more at a wavelength in the visible range (380 to 780 nm), can be preferably applied to the resin base material according to the present invention. In addition, the material of this resin base material can be used individually or in combination of 2 or more types. Further, the resin substrate may be a single layer or a multilayer of two or more layers.

  The resin substrate used in the present invention can be subjected to a surface treatment or an easy-adhesion layer in order to ensure the wettability and adhesion of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. Examples of the surface treatment include corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and surface activation treatment such as laser treatment. Examples of the easy adhesion layer include a layer containing polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, or epoxy copolymer. Can be mentioned. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

  The thickness of the resin substrate is not particularly limited, but is preferably 5 to 200 μm, and more preferably 15 to 150 μm.

<Underlayer>
It is preferable to provide an undercoat layer between the photocatalyst layer of the present invention and the resin base material. The undercoat layer used in the present invention is more preferably an undercoat layer using an inorganic material because it is not decomposed by photocatalysis. By providing the undercoat layer, not only the durability of the substrate is increased, but also the adhesiveness between the substrate and the photocatalyst layer is increased, so that the film physical properties and the light extraction efficiency on the surface of the photocatalyst layer are also increased.

  Examples of the inorganic material contained in the undercoat layer include amorphous titanium oxide, silica, polysilazane, and polysiloxane oligomer. These inorganic materials can be used alone or in combination of two or more. The method for forming the undercoat layer is not particularly limited, and examples thereof include a coating method and a sputtering method. In particular, when polysilazane is used as the inorganic material, the undercoat layer is formed and the photocatalyst layer is formed by irradiating vacuum ultraviolet light after simultaneously applying the photocatalyst layer coating solution and the polysilazane-containing undercoat coating solution. Can be formed at the same time, and adhesion and productivity are further improved.

  The thickness of the undercoat layer is not particularly limited, but is preferably 30 to 1000 nm.

(Method for producing photocatalyst)
If the photocatalyst layer can be formed so that the content per unit volume of the photocatalyst particles increases continuously or stepwise from the resin base material side to the surface side of the photocatalyst layer according to the present invention, Any method is acceptable. For example, a method in which coating solutions having different concentrations of photocatalyst particles are sequentially applied from the resin substrate side, dried and laminated; a step of mixing a metal oxide and an organometallic compound to prepare a mixed solution; and Examples of the method include a step of applying a coating on a resin substrate and drying to obtain a coating film, and a step of irradiating the coating film with vacuum ultraviolet light having a wavelength of 200 nm or less.

  However, from the viewpoint of producing a photocatalyst that is highly productive, suitable for continuous production, exhibits good photocatalytic activity by visible light irradiation, and hardly deteriorates film properties even when used for a long period of time, metal oxidation. A step of preparing a mixed solution by mixing a product and an organometallic compound, a step of applying the mixed solution on the resin substrate and drying to obtain a coating film, and applying vacuum ultraviolet light having a wavelength of 200 nm or less to the coating film And a step of irradiating is preferable. Hereinafter, a method for producing such a preferable photocatalyst will be described in detail.

<Step of preparing a mixed solution>
In this step, a metal oxide and an organometallic compound are mixed in a solvent to prepare a mixed solution.

  The metal oxide is a photocatalytic substance having a photocatalytic function or a substance to be a metal compound supported on the photocatalytic substance, and the organometallic compound is formed on a precursor of the photocatalytic substance having a photocatalytic function or on the photocatalytic substance. It is a substance that becomes a precursor of a supported metal compound. As the form, (1) the metal oxide is the photocatalytic substance, the organometallic compound is a precursor of the metal compound, and (2) the organometallic compound is the precursor of the photocatalytic substance. A form in which the metal oxide is the metal compound.

  Specific examples of the metal oxide used as the photocatalytic substance used in the form (1) include titanium oxide, zinc oxide, and tungsten oxide. Moreover, as a specific example of the organometallic compound used as the precursor of the metallic compound used with the form of said (1), organic iron compounds, such as iron naphthenate, iron acetylacetone, iron 2-ethylhexanoate, bis [ (S) -2-Hydroxypropionic acid] Organic copper compounds such as copper (II) and copper ethoxide.

Specific examples of the organometallic compound used as the precursor of the photocatalytic substance used in the above form (2) include, for example, tetraethyl orthotitanate, titanium tetra-2-ethylhexoxide, titanium lactate, titanium tetraacetylacetate. And organic titanium compounds such as tungsten (V) isopropyl oxide and tungsten (V) ethoxide. Moreover, as a specific example of the metal oxide used as the metal compound used in the above form (2), for example, platinum oxide (PtO ₂ ), gold oxide (Au ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ). And at least one selected from the group consisting of copper oxide (CuO).

  Among these forms, the form of (1) is preferable from the viewpoint that the support of the metal compound on the photocatalytic substance becomes more uniform and higher photocatalytic performance can be obtained.

  Examples of the solvent of the mixed solution include hydrocarbons such as toluene, hexane, benzene, xylene, and ethylbenzene, alcohols such as methanol, ethanol, propanol, and isopropyl alcohol, ethyl acetate, butyl acetate, isobutyl acetate, and propyl acetate. And esters.

  In the case of the above form (1), the concentration of the metal oxide in the mixed solution is preferably 30 to 80% by mass, and the concentration of the organometallic compound in the mixed solution is 0.00003 to 0.08 mass. % Is preferred. In the case of the form (2), the concentration of the metal oxide in the mixed solution is preferably 0.00003 to 0.08% by mass, and the concentration of the organometallic compound in the mixed solution is 30 to It is preferable that it is 80 mass%.

  When obtaining a photocatalyst layer having a binder, a binder is added to the mixed solution. Since the specific example of a binder is the same as that of the above, description is abbreviate | omitted here.

  In addition, in the production method as described above, the lower the crystallinity of the metal oxide, the better the bondability between the photocatalyst substance and the metal compound in the finally obtained photocatalyst particles, and the adhesion of the photocatalyst layer to the substrate. Is more preferable.

<The process of apply | coating a liquid mixture on a resin base material, and drying>
In this step, the mixed solution prepared in the above step is applied onto a resin substrate and dried. Thereby, the coating film which consists of solid content in a liquid mixture is obtained.

  Application method is not particularly limited, for example, natural coater, knife belt coater, floating knife, roll coat, air knife coat, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, air blade And various coating methods using apparatuses such as curtain flow coaters, doctor blades, wire bars, die coaters, comma coaters, spin coaters, baker applicators, and gravure coaters.

  Although the drying conditions are not particularly limited, it is preferable to dry at a temperature of 25 to 200 ° C. for 5 to 30 minutes.

  When an undercoat layer is to be installed, it may be installed in advance before this step. In this step, the undercoat layer coating solution is applied onto the resin substrate by simultaneous multilayer coating with the mixed solution. It may be applied and installed. Examples of the simultaneous multilayer coating method include a slide hopper coating method and an extrusion coating method described in US Pat. No. 2,761,419, US Pat. No. 2,761,791, and the like. .

<Step of irradiating vacuum ultraviolet light with a wavelength of 200 nm or less>
In this step, the coating film obtained above is irradiated with vacuum ultraviolet light having a wavelength of 200 nm or less. Thereby, the said coating film is converted into a photocatalyst layer.

  This step uses light energy of 100 to 200 nm, which is larger than the interatomic bonding force in the compound, and the oxidation of the active oxygen or ozone while directly cutting the atomic bond by the action of only the photon called the photon process. By allowing the reaction to proceed, the photocatalyst layer is formed under relatively low temperature conditions. By this step, (a) the oxidation of the organometallic compound, (b) the loading of the metal compound on the photocatalytic substance, and (c) the content distribution of the photocatalytic particles can be performed at the same time, and the productivity is improved. High manufacturing method suitable for continuous production.

Examples of the vacuum ultraviolet light include excimer light and F ₂ laser, and excimer light is preferable.

As a light source for vacuum ultraviolet light, a rare gas excimer lamp is preferably used. Atoms of noble gases such as Xe, Kr, Ar, and Ne are called inert gases because they are not chemically bonded to form molecules. However, a rare gas atom (excited atom) that has gained energy by discharge or the like can combine with other atoms to form a molecule. When the rare gas is xenon,
e + Xe → e + Xe ^*
Xe ^* + Xe + Xe → Xe ₂ ^* + Xe
Thus, when the excited excimer molecule Xe ₂ ^* transitions to the ground state, excimer light of 172 nm is emitted. A feature of the excimer lamp is that the radiation is concentrated on one wavelength, and since only the necessary light is not emitted, the efficiency is high. In addition, the Xe excimer lamp can be preferably used because the luminous efficiency is higher than that of other rare gases and a lamp for irradiating a large area can be made of quartz glass.

  From the standpoint of energy only, Ar excimer light (wavelength 126 nm) has the highest energy. However, since Ar excimer light becomes so large that absorption in quartz glass cannot be ignored, it is necessary to use calcium carbonate glass instead of silicon dioxide glass. However, the fact is that calcium carbonate glass is very fragile and is difficult to manufacture as a lamp that irradiates a large area.

  The Xe excimer lamp is excellent in luminous efficiency because it emits ultraviolet light having a short wavelength of 172 nm at a single wavelength. Since this light has a large oxygen absorption coefficient, it can generate radical oxygen atom species and ozone at a high concentration with a very small amount of oxygen. In addition, it is known that the energy of light having a short wavelength of 172 nm for dissociating the bonds of organic substances has high ability. The film can be reformed in a short time by the high energy of this active oxygen, ozone and ultraviolet radiation. Therefore, compared with low-pressure mercury lamps with wavelengths of 185 nm and 254 nm and plasma cleaning, it is possible to shorten the process time associated with high throughput, reduce the equipment area, and irradiate organic materials and plastic substrates that are easily damaged by heat. .

  As an atmosphere during excimer irradiation, the oxygen concentration is preferably 0.001 to 5% by volume. Furthermore, it is more preferable that the oxygen concentration is 0.01 to 3% by volume because the performance is stable. When the oxygen concentration exceeds 5% by volume, energy is used to generate active oxygen rather than bond breakage, and even if the oxygen concentration is reduced to less than 0.001% by volume, the excimer light irradiation efficiency is hardly changed. Furthermore, the reforming efficiency and the composition controllability of the film do not change, and the time for replacing oxygen is necessary, so that it is difficult to obtain the effect of improving productivity. As the gas other than oxygen, a dry inert gas is preferably used, and dry nitrogen gas is more preferably used from the viewpoint of cost. The oxygen concentration can be adjusted by measuring the flow rates of oxygen gas and inert gas introduced into the irradiation chamber and changing the flow rate ratio.

  The stage temperature is preferably high to some extent because the reaction is more likely to proceed when heat is applied. In this case, the temperature is preferably 50 ° C. or higher and the glass transition point (Tg) of the resin base material + 80 ° C. or lower, and the temperature range of 50 ° C. or higher and the resin base Tg + 30 ° C. or lower is preferable. Since the reactivity of the photocatalyst layer is improved without damaging the above, it is more preferable.

  If the irradiation intensity is high, the modification reaction can be shortened. In addition, since the number of photons penetrating into the interior increases, the film quality can be improved (densification). However, if the irradiation time is too long, the planarity may be deteriorated or other materials may be damaged. In general, the reaction progress is considered by the integrated light quantity expressed by the product of the irradiation intensity and the irradiation time. However, the absolute value of the irradiation intensity is the same for the materials having the same composition but having various structural forms. It can be important.

The integrated irradiation energy is not particularly limited, but is preferably 1000 to 10,000 mJ / cm ² .

(Use)
The photocatalyst of the present invention has functions such as environmental purification, deodorization, antifouling, and sterilization, and can be used for applications that require these functions. Specifically, application to electronic devices, interior members, air purifiers, and the like is preferable. Among these, an electronic device using a visible light source such as an organic EL, LED, or fluorescent lamp is particularly preferable. Electronic devices using visible light sources are lighting, display devices, displays, etc., for example, home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, electrophotography Examples include a light source of a copying machine, a light source of an optical communication processor, and a light source of an optical sensor.

  Examples of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following description, “part” or “%” is used, but “part by mass” or “% by mass” is expressed unless otherwise specified. The content of photocatalyst particles was measured by the following method.

[Measurement of photocatalyst particle content]
The obtained photocatalyst layer is etched from the surface in the depth direction using an ion etching method, and the surface of the photocatalyst layer is obtained using an X-ray photoelectron spectrometer (ESCA LAB-200R, manufactured by VG Scientific). The amount of the metal compound or the amount of the photocatalytic substance (photocatalyst particles) carrying the metal compound was measured every 10 nm. Table 1 shows the ratio of the measured value at the position of 10 nm from the surface to the value obtained by averaging the measured values every 10 nm from the surface to the resin base material, and the ratio of the measured value on the near side 10 nm from the resin base material to the averaged value. Indicated.

Example 1
[Production of photocatalyst]
Fe ₂ O ₃ particles were added to a toluene solution having a titanium tetra-2-ethylhexoxide concentration of 50 mass% so that the ratio of iron to titanium oxide (TiO ₂ ) was 0.1 mass%. Furthermore, polyorganosiloxane (manufactured by JSR Corporation, Glasca) was added so as to be 0.25% by mass with respect to TiO ₂ to prepare a photocatalyst layer coating solution 1. The photocatalyst layer coating solution 1 was applied on a polyethylene naphthalate (PEN) film having a thickness of 50 μm using a spin coater so that the film thickness after drying was 400 nm, and dried at 150 ° C. for 10 minutes. Photocatalyst body 1 was produced by irradiating with vacuum ultraviolet light under the following conditions.

[Vacuum UV irradiation conditions]
The photocatalyst after drying the coating solution is moved to 80 ° C. at a moving speed in an apparatus chamber in which appropriate amounts of nitrogen and oxygen are supplied so that water vapor is substantially removed and the oxygen concentration is maintained at 0.1% by volume. It was supplied at 0.6 mm / min. Excimer light was irradiated under the conditions of an irradiation distance of 3 mm, a maximum illuminance of 90 mW / cm ² , and an integrated irradiation energy of 2000 mJ / cm ² using a Xe excimer lamp having a double tube structure that irradiates vacuum ultraviolet rays of 172 nm. In this case, the integrated irradiation energy was measured using an ultraviolet integrated light meter manufactured by Hamamatsu Photonics Co., Ltd .: C8026 / H8025 UV POWER METER. Prior to measurement, in order to stabilize the illuminance of the Xe excimer lamp, an aging time of 10 minutes was provided after the Xe excimer lamp was turned on.

  When the photocatalyst body 1 was observed by an X-ray photoelectron spectroscopic analyzer (XPS method) using an ion etching method, the content of titanium oxide in the photocatalyst layer was directed from the resin substrate side to the surface side of the photocatalyst layer. It was confirmed that the number increased continuously.

(Example 2)
60 g of titanium tetrachloride aqueous solution (Ti content: 17.0% by mass) was added dropwise to 690 mL of 80 ° C. pure water at 1 g / min, followed by stirring at 85 ° C. for 60 minutes, and the resulting sol was adjusted to pH 4 by electrodialysis. A dechlorination treatment was performed, and further dried at 120 ° C. for 24 hours to produce titanium oxide (TiO ₂ ). 50 wt% toluene solution of TiO ₂ produced as the proportion of iron is 0.1% by weight with respect to TiO _2, 2-ethylhexanoate, iron was added, further polyorganosiloxanes (JSR Corporation, The photocatalyst layer coating solution 2 was prepared by adding 0.25% by mass of silicate glass) to TiO ₂ . This photocatalyst layer coating solution 2 was applied on the PEN film so that the film thickness after drying was 400 nm, dried at 150 ° C. for 10 minutes, and then irradiated with vacuum ultraviolet light in the same manner as the photocatalyst 1. Photocatalyst body 2 was produced.

  FIG. 1 is a graph showing the results of measuring the change in the thickness direction of the iron oxide content in the photocatalyst layer of the photocatalyst 2 by the above-mentioned [Measurement of content of photocatalyst particles] (XPS method). As can be seen from FIG. 1, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer.

(Example 3)
A photocatalyst 3 was produced in the same manner as in Example 2 except that a silica undercoat layer was previously formed on the PEN film by the sputtering method described below.

[Silica undercoat layer formation (sputtering method)]
An RF magnetron sputtering apparatus was used, a SiO ₂ target with a purity of 99.9% or higher was used, and argon and oxygen were used as the introduced gas, with an applied power of 200 W, 13.56 KHz, and a degree of vacuum of 8 × 10 ⁻⁴ Pa (6 A silica undercoat layer having a thickness of 0.6 μm was prepared under the conditions of × 10 ⁻⁶ Torr), gas pressure 3.07 Pa (23 mTorr), gas distribution rate Ar / O ₂ = 20/3, and substrate temperature of 300 ° C.

  When the photocatalyst body 3 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer in the same manner as the photocatalyst body 2.

Example 4
The following titanium alkoxide hydrolysis condensate is applied onto a PEN film using a spin coater so that the film thickness upon drying is 50 nm, dried at 80 ° C. for 10 minutes, and an undercoat layer containing amorphous titanium oxide A photocatalyst 4 was produced in the same manner as in Example 2 except that was formed.

(Titanium alkoxide hydrolysis condensate)
To 150 g of ethyl cellosolve, 75 g of titanium tetraisopropoxide (trade name: A-1, Nippon Soda Co., Ltd.) was added dropwise with stirring. To this solution, 58 g of ethyl cellosolve, 4.5 g of distilled water, 60% by mass concentrated nitric acid 13 g was added dropwise with stirring, and the mixture was stirred at 30 ° C. for 4 hours to obtain a titanium alkoxide hydrolysis condensation liquid.

  When the photocatalyst body 4 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin base material side to the surface side of the photocatalyst layer as in the photocatalyst body 2.

(Example 5)
Example 2 except that the following polysilazane coating solution was applied on a PEN film using a wireless bar so that the film thickness after drying was 200 nm and dried at 100 ° C. for 2 minutes to form an undercoat layer. In the same manner as above, a photocatalyst 5 was produced.

[Polysilazane coating solution]
A dibutyl ether solution containing 20% by mass of non-catalytic perhydropolysilazane (manufactured by AZ Electronic Materials Co., Ltd., Aquamica (registered trademark) NN120-20), and 20 of perhydropolysilazane containing 5% by mass of an amine catalyst in solid content. A mass% dibutyl ether solution (manufactured by AZ Electronic Materials Co., Ltd., Aquamica (registered trademark) NAX120-20) was prepared so that the amine catalyst had a solid content of 1% by mass, and the total solid content was 5% by mass. The solution was diluted with dibutyl ether to prepare a polysilazane coating solution.

  When the photocatalyst body 5 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer as in the photocatalyst body 2.

(Example 6)
A photocatalyst 6 was produced in the same manner as in Example 5 except that copper ethoxide was used instead of iron 2-ethylhexanoate.

  When the photocatalyst body 6 was observed by the XPS method, it was confirmed that the content of copper oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer in the same manner as the photocatalyst body 2.

(Example 7)
Instead of polyorganosiloxane, 0.1% by mass of fluoropolymer (manufactured by Asahi Glass Co., Ltd., Lumiflon (registered trademark) LF200) with respect to TiO ₂ is added, and further, an isocyanate-based curing agent 0.02 is added to the photocatalyst layer coating solution 2. A photocatalyst 7 was produced in the same manner as in Example 2 except that mass% was added.

  When the photocatalyst body 7 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin base material side to the surface side of the photocatalyst layer as in the photocatalyst body 2.

(Example 8)
A photocatalyst 8 was produced in the same manner as in Example 7 except that a vinyl acetate-acrylic copolymer (manufactured by DIC Corporation, Boncoat (registered trademark)) was used instead of polyorganosiloxane.

  When the photocatalyst body 8 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer, as in the photocatalyst body 2.

Example 9
A photocatalyst 9 was prepared in the same manner as in Example 5 except that no polyorganosiloxane was used.

  When the photocatalyst body 9 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer in the same manner as the photocatalyst body 2.

(Example 10)
Photocatalyst body 10 was produced in the same manner as Example 5 except that anatase-type titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., ST-01) was used as the titanium oxide particles.

  When the photocatalyst body 10 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer in the same manner as the photocatalyst body 2.

(Example 11)
A photocatalyst 11 was produced in the same manner as in Example 6 except that tungsten oxide (WO ₃ ) produced as follows was used instead of titanium oxide (TiO ₂ ).

[Production of tungsten oxide]
500 g of ammonium metatungstate aqueous solution (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., MW-2) was dried at 110 ° C. for 18 hours, further calcined at 500 ° C. for 1 hour, washed and dried to obtain tungsten oxide particles.

  When the photocatalyst body 11 was observed by the XPS method, it was confirmed that the content of iron oxide was continuously increased from the resin substrate side to the surface side of the photocatalyst layer in the same manner as the photocatalyst body 2.

(Example 12)
Anatase type titanium oxide (Ishihara Sangyo Co., Ltd., ST-01) was annealed at 550 ° C. for 3 hours in an ammonia stream (1SCCM) to prepare nitrogen-doped titanium oxide particles. FeCl ₃ .2H ₂ O (manufactured by Wako Pure Chemical Industries, Ltd.) is added to a 10% by mass aqueous solution of the nitrogen-doped titanium oxide particles so that the ratio of iron to TiO ₂ is 0.1% by mass and stirred. The mixture was heated to 90 ° C. and held for 1 hour. The aqueous solution was subjected to suction filtration, washed, and dried by heating at 110 ° C. to obtain titanium oxide particles carrying iron oxide.

  After applying and drying the polysilazane coating solution in the same manner as in Example 5, the titanium oxide carrying the iron oxide on the PEN film formed with an undercoat layer by irradiation with vacuum ultraviolet light in the same manner as in Example 1 The photocatalyst layer coating solution prepared by using the particles according to the following formulation was applied and dried so that the film thickness after drying was 100 nm. Then, after drying the photocatalyst layer coating solution prepared so that the mixing ratios of titanium oxide and polyorganosiloxane in the photocatalyst layer coating solution below were 5: 8, 8: 5, and 10: 3 (weight ratio), respectively. The film was sequentially applied and dried so that each of the film thicknesses became 100 nm, and a photocatalyst body 12 having a total of 400 nm of photocatalyst layer was obtained.

[Photocatalyst layer coating solution]
3 g of titanium oxide carrying iron oxide, 10 g of polyorganosiloxane (manufactured by JSR Corporation, Glasca), 22 ml of isopropyl alcohol.

(Comparative Example 1)
A photocatalyst layer coating solution having a mixing ratio of titanium oxide and polyorganosiloxane of 10: 3 (weight ratio) was dried on a PEN film having an undercoat layer in the same manner as in Example 12, and the film thickness after drying was 400 nm. The photocatalyst body 13 was obtained by applying and drying.

(Comparative Example 2)
A toluene solution having a tetraethyl orthotitanate concentration of 50% by mass was applied onto a PEN film so that the film thickness upon drying was 400 nm, dried at 150 ° C. for 10 minutes, and then the same method as in Example 1. The photocatalyst body 14 was obtained by irradiation with vacuum ultraviolet light.

(Comparative Example 3)
Comparative Example 2 except that iron 2-ethylhexanoate was added to a toluene solution having a tetraethyl orthotitanate concentration of 50% by mass so that the ratio of iron to TiO ₂ was 0.1% by mass. Thus, a photocatalyst body 15 was produced.

(Evaluation of photocatalyst)
Evaluation of photocatalytic performance and film stability after long-term lighting was performed using an organic EL lighting device in which an organic EL layer was formed on a photocatalyst as follows.

[Production of organic EL layer]
This ITO conductive layer is formed by patterning ITO (indium tin oxide: refractive index 1.85) to a thickness of 100 nm on a photocatalyst resin substrate (on the surface where the photocatalyst layer is not present). The substrate provided with was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. On this substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron (registered trademark) P Al 4083) to 70% with pure water at 3000 rpm, After forming a film by spin coating under the condition of 30 seconds, it was dried at a substrate surface temperature of 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

  This substrate was transferred to a glove box having a cleanness measured in accordance with JIS B 9920: 2002 of class 100, a dew point temperature of −80 ° C. or lower, and an oxygen concentration of 0.8 ppm in a nitrogen atmosphere. A coating solution for a hole transport layer, which is the following component, was prepared in a glove box, and applied with a spin coater under conditions of 1500 rpm and 30 seconds. This substrate was dried by heating at a substrate surface temperature of 150 ° C. for 30 minutes to provide a hole transport layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

<Coating liquid for hole transport layer>
Monochlorobenzene 100 g, poly-N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine (ADS254BE: manufactured by American Die Source) 0.5 g.

  Next, a light emitting layer coating solution was prepared as described below, and applied with a spin coater under the conditions of 2000 rpm and 30 seconds. Furthermore, it heated for 30 minutes at the substrate surface temperature of 120 degreeC, and provided the light emitting layer. When the coating was performed under the same conditions on a separately prepared substrate and measured, the film thickness was 40 nm. Of the components in the following light emitting layer coating solution, HA showed the lowest Tg, which was 132 ° C.

<Coating solution for light emitting layer>
100 g of butyl acetate, 1 g of a compound represented by HA in the following chemical formula (1), 0.11 g of a compound represented by DA in the following chemical formula (1), and DB in the following chemical formula (1) 0.002 g of a compound to be obtained, 0.002 g of a compound represented by DC in the following chemical formula (1).

  Subsequently, the coating liquid for electron carrying layers was prepared as follows, and it apply | coated on the conditions of 1500 rpm and 30 seconds with a spin coater. Furthermore, it heated for 30 minutes at the substrate surface temperature of 120 degreeC, and provided the electron carrying layer. The film thickness was 30 nm when it applied and measured on the conditions prepared with the board | substrate prepared separately.

<Coating liquid for electron transport layer>
100 g of 2,2,3,3-tetrafluoro-1-propanol, 0.75 g of the compound represented by ET-A in the chemical formula (1).

Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. Note that potassium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.

  First, a resistance heating boat containing potassium fluoride was energized and heated, and an electron injection layer made of potassium fluoride was provided on the substrate with a thickness of 3 nm. Subsequently, a resistance heating boat containing aluminum was energized and heated, and a cathode having a film thickness of 100 nm made of aluminum was provided at a deposition rate of 1 to 2 nm / second.

[Photocatalytic performance]
Acetaldehyde gas was injected into the sealed container so as to be 80 to 100 ppm, and left in a dark place for 30 minutes. Thereafter, the organic EL lighting device is inserted into the sealed container, and the gas concentration after lighting for 24 hours at 23 ° C. is A. Similarly, the organic EL lighting device is not turned on in the sealed container for 24 hours at 23 ° C. The gas concentration after being allowed to stand was defined as B. From the gas concentrations A and B, the photocatalytic performance was determined according to the following formula.

Photocatalytic performance (%) = (B−A) / B × 100
[Membrane stability after long-term lighting]
Using the same organic EL lighting device as that used for the evaluation of the photocatalytic performance, the evaluation of the adhesiveness of the photocatalyst layer after continuing to light for 720 hours under the conditions of 50 ° C. and 60% RH was performed according to JIS K5600- 5-6 (ISO 2409): Adhesiveness—Tests were performed according to the cross-cut method, and evaluation was performed in five stages according to the following classification. The larger the number is, the more easily the photocatalyst layer is peeled off, indicating that the film properties after long-term lighting are poor.

  Table 1 shows the evaluation results of the photocatalysts obtained in each Example and each Comparative Example.

  As is clear from Table 1 above, the photocatalyst of the present invention exhibits good photocatalytic activity, and hardly deteriorates in film properties or brightness even after long-term lighting.

Claims (7)

On the resin substrate, it has a photocatalyst layer containing photocatalyst particles in which a metal compound is supported on a photocatalyst substance,
The photocatalyst body in which the content per unit volume of the photocatalyst particles increases continuously or stepwise from the resin substrate side of the photocatalyst layer toward the surface side of the photocatalyst layer.   The photocatalyst body according to claim 1, wherein the increase in the content per unit volume of the photocatalyst particles is continuous.   The photocatalyst body according to claim 1 or 2, wherein the photocatalyst layer includes at least one binder selected from the group consisting of a fluoropolymer and a silicon compound. A method for producing a photocatalyst having a photocatalyst layer on a resin substrate,
A step of mixing a metal oxide and an organometallic compound to prepare a mixed solution;
Applying the mixed solution onto the resin substrate and drying to obtain a coating film;
Irradiating the coating film with vacuum ultraviolet light having a wavelength of 200 nm or less;
A method for producing a photocatalyst body, comprising:   The manufacturing method of Claim 4 with which the said liquid mixture contains the at least 1 sort (s) of binder selected from the group which consists of a fluoropolymer and a silicon compound.   The production method according to claim 4 or 5, wherein the metal oxide is a photocatalytic substance, and the organometallic compound is a precursor of a metal compound supported on the photocatalytic substance.   The electronic device which provided the photocatalyst body of any one of Claims 1-3, or the photocatalyst body obtained by the manufacturing method of any one of Claims 4-6.